ERROR: No matching distribution found for kivy_deps.sdl2==0.1.22 (from -r requirements.txt (line 4))
Tried both pip install kivy_deps.sdl2 and pip3 install kivy_deps.sdl2
Reading through some kivy GH issues imply that the kive_deps bits are for Windows only.
It looks like they are still working on distributing Python 3.8 wheels and their documentation also states
Linux wheels are new and still experimental, if you run into issues, uninstall it and use any of the other installation methods listed further down.
https://kivy.org/doc/stable/installation/installation-linux.html
So you might have to build this from source.